1. Field of the Invention
The present invention relates to a display device, and more particularly to a display device having flexibility.
2. Related Background Art
Active matrix type display devices in which active elements such as TFTs are arranged at pixels can realize flat type display devices with high image quality. As display parts of the active matrix type display devices, liquid crystal being a light shutter, organic EL which emits light, and electrophoretic devices (enclosed in microcapsules or not), can be used. These active matrix type display devices, having a thin profile and lightweight, are therefore most suitable for display devices of portable information equipment such as a notebook personal computer or PDA which can be carried.
It is conceivable that portable information equipment will be used more widely in the future with radio network improvements, and therefore display devices of the portable information equipment are required to be further reduced in thickness and weight. In response to this requirement, an active matrix type display device using a plastic substrate is proposed. Its examples include a transfer method of taking active elements, which have been formed on a heat-resistant substrate such as a glass substrate in advance, out of the glass substrate and transferring them onto a plastic substrate, a method of forming active elements directly on a plastic substrate by an ultra-low temperature process, and a method of forming organic transistors on a plastic substrate. By these methods, it is possible not only to reduce display devices in thickness and weight but also to make them flexible so that the devices can be bent.
As flexible display devices, there are known examples in which the display devices can be accommodated rolled or folded. For example, see Japanese Patent Laid-open No. Hei 11-272205 (P. 2–8, FIG. 1), and Japanese Patent Laid-open No. Hei 10-257143 (P. 3–5, FIG. 1).
However, the above-described display devices have a problem that they have complicated structures, and therefore a bendable display device with a simple configuration has been desired.